To establish (REF ), we note that by virtue of a standard trace inequality (see, e.g., [1]})
\(\Vert  v \Vert ^2_{T \cap \partial \Omega _D} \lesssim h^{-1} \Vert  v \Vert ^2_T + h \Vert  \nabla v \Vert ^2_T \qquad v \in H^1(T)\) 
